二碘化钐促进的二硫代氨基甲酸酯和硫代氨基甲酸酯的还原断裂反应

室温下SmI2-THF-HMPA-t-BuOH体系可顺利地将二硫代氨基甲酸酯还原断裂得到二硫醚和硫代甲酰胺; 同样条件下, 硫代氨基甲酸酯还原断裂得到二硫醚篅34The reductive cleavage of dithiocarbamic esters are promoted by the SmI2-HMPA-THF-t-BuOH System successfully to give disulfides and thiocarboxamides at room temperature in good yields; The reduction of thiocarbamic esters are also promoted by the same system to give disulfides and carboxamides.     

二硫化碳对机体铜、锌水平的影响

为观察二硫化碳（CS2）对机体铜，锌水平的影响，对某化纤厂35名接触CS2工人和41名非接触工人的血铜，锌值进行调查，比较，并进行了动物染毒实验。SD大鼠吸入CS2浓度分别为5和50mg/m^3，每日5h，每周6d，连续6个月，于染毒2，4，6个月时测定血浆铜，锌值及染毒6个月时肝脏铜，锌含量。结果显示，CS2接触组工人血铜，锌水平较对照组显著降低（P＜0．05）。在CS2染毒6个月时，50mg/m^3 CS2染毒组血浆及肝脏铜水平均较对照组及5mg/m^3 CS2染毒组显著降低（P＜0．05）。可见接触CS2能干扰机体铜，锌代谢，导致体内铜，锌含量减少。     

1H NMR Study of Hindered Internal Rotation of Tetramethylthiuram Disulfide in Binary Dimethyl Sulfoxide‐Chloroform Mixtures

Hindered internal rotation about the C‐N single bonds joining the thiuram disulfide was studied by ¹H NMR complete line‐shaped analysis in different dimethyl sulfoxide‐chloroform (DMSO‐CDCl₃) mixtures. From the temperature dependence of methyls proton spectra, activation parameters (E_a, ΔH^≠, ΔS^≠, and ΔG^≠) were obtained. The Arrhenius plots showed a distinct isokinetic temperature at about 35 °C at which the exchange rate is more or less independent of the solvent composition. The resulting ΔH^≠ against TΔS^≠ plot showed a firmly good linear correlation, indicating the existence of an enthalpy‐entropy composition in an exchange process.     

A high yielding, one-pot synthesis of O,S-dialkyl dithiocarbonates from alcohols using Mitsunobu’s reagent

A novel Mitsunobu-based protocol has been developed for the synthesis of O,S-dialkyl dithiocarbonates from a variety of primary, secondary and tertiary alcohols using carbon disulfide, in good to excellent yields. This protocol is mild and efficient compared to other reported methods.     

Electrochemical Behavior of Diphenyl Disulfide and Thiophenol on Glassy Carbon and Gold Electrodes in Aprotic Media

The investigation of the electrochemical reduction processes of C₆H₅SSC₆H₅ and C₆H₅SH in CH₃CN using cyclic voltammetry indicates a different behavior on GC and Au electrodes. On GC surface adsorption phenomena are absent, the electrochemical reduction process is irreversible and diffusion controlled. For both the starting molecules the same species, C₆H₅S^?, is formed upon reduction. The E° values of the reduction processes were determined by convolution method and the standard free energy of the S? S bond of C₆H₅SSC₆H₅ estimated. On Au surface instead, a self‐assembled monolayer of C₆H₅SAu_ads originated after the S? S or S? H bond breaking can be observed by simply dipping the electrode in solution of C₆H₅SSC₆H₅ and C₆H₅SH, respectively. The properties of the SAM were investigated by electrochemical reduction of the adsorbed thiolates. On Au electrode the reduction processes involve C₆H₅SAu_ads and give rise to desorbed C₆H₅S^?. A neutral radical is obtained by electrochemical oxidation of thiolate anion. It reacts rapidly with the electrode surface to give the S‐Au bond again.     

Structure control within poly(amidoamine) dendrimers: size, shape and regio-chemical mimicry of globular proteins

This work describes the syntheses of a new poly(amidoamine) (PAMAM) dendrimer family possessing a disulfide function (cystamine) in its core. Traditional redox-chemistry associated with the disulfide core in these dendrimer structures, provides a versatile strategy for designing unique sizes, shapes and controlling the regio-disposition of chemical groups on the surface of these dendrimers. Various single site, sulfhydryl functionalized dendron reactants may be generated in situ, under standard reducing conditions (i.e. dithiothreitol (DTT)). Facile control of size, shape and chemical functionality placement involves covalent hybridization of these single point, sulfhydryl reactive dendron components. This is accomplished by re-oxidation in the presence of air, to yield generation/surface chemistry differentiated cross-over products which may be isolated by preparative thin layer or column chromatography. Differentiated cystamine core dendrimers derived from combination and permutation of lower generation (i.e. Gen.=0-3) sulfhydryl functionalized dendrons possessing amino, hydroxyl, acetamido or dansyl surface groups, were synthesized and isolated. They were characterized by a variety of methods including; ¹³C NMR, capillary electrophoresis (CE), gel electrophoresis (PAGE), thin layer chromatography (TLC) and electrospray (ES) or matrix assisted laser desorption ionization (MALDI-TOF) mass spectrometry. This general strategy has broad implications for the systematic size, shape and regio-chemical control of a wide range of dendritic nanostructures, many of which may be designed to mimic the sizes, shapes and regio specific chemo-domains observed for globular proteins.     

Immobilization of copper in organic-inorganic hybrid materials: a highly efficient and reusable catalyst for the Ullmann diaryl etherification

The immobilization of copper in organic-inorganic hybrid materials catalyzing the Ullmann reaction has been described. Phenols reacted with aryl iodides, aryl bromides and aryl chlorides smoothly in the presence of a 3-(2-aminoethylamino)propyl functionalized silica gel immobilized copper catalyst. The protocol involved the use of DMSO as the solvent, and potassium fluoride as the base. The reactions generated the corresponding cross-coupling products in good to excellent yields. Furthermore, the silica-supported copper could be recovered and recycled by a simple filtration of the reaction solution and used for 10 consecutive trials without loss of its reactivity.     

Studies on Aggregation Interaction between Reduced Denatured Egg White Lysozymes during Refolding Procedure in Urea Solution

The aggregation interaction between reduced-denatured egg white lysozymes during refolding procedure in urea solution was studied by means of reducing and non-reducing protein electrophoreses. Results of non-reducing sodium dodecyl sulphate polyacrylamide gel electrophoresis （SDS-PAGE） of the supernatant and aggregate precipitate formed in refolding process show that except being refolded to native egg white lysozymes, the reduced-denatured lysozymes can also form the aggregates with molecular weights （MW） being separately about 30.0 and 35.0 kD, while the reducing SDS-PAGE and the refolding results in the presence of sodium dodecyl sulphate show that these aggregates are formed chiefly through the misconnection of disulfide bonds between the reduced-denatured lysozymes, and the aggregate precipitates are formed through the non-covalent interactions between the aggregates with molecular weight being about 30.0 kD. From the results of electrophoresis and size-exclusion chromatographic analyses, it can be inferred that the aggregates with molecular weights being about 30.0 and 35.0 kD are bi-molecular and tri-molecular egg white lysozyme aggregates, respectively. And finally, a suggested refolding mechanism of reduced-denatured egg white lysozymes in urea solution was presented.     

A concise method for synthesis of diaryl aryl- or alkylphosphonates

A convenient method has been developed to synthesize diaryl arylphosphonates from triaryl phosphites, triethyl phosphite, and aromatic halides. The new method relies on the triethyl phosphite assisted nickel catalyzed Arbuzov reaction and can be applied to synthesize certain diaryl alkylphosphonates without catalysts.     

PVC DISULFIDE AS CATHODE MATERIALS FOR SECONDARY LITHIUM BATTERIES

PVC disulfide (2SPVC) was synthesized by solution crosslink and its molecular structure was confirmed by infrared spectrum. 2SPVC's specific area is 36.1 m2·g-1 tested by stand BET method, and granularity experiment gives out the particle size of d0.5= 11.3μm. With SEM (Scanning Electron Microscope) experiment the surface morphology and particle shape of 2SPVC were observed. Cyclic voltammetry (scan rate: 0.5 mV·s-1) shows that 2SPVC experience an obvious S-S redox reaction in charge-discharge process. When 2SPVC was used as cathode material for secondary lithium battery in a 1 mol·L-1 solution of lithium bis(trifluoromethylsulfonyl) imide (Li(CF3SO2)2N) in a 5:45:50 volume ratio mixture of o-xylene (oxy), diglyme (DG) and dimethoxymethane (DME) at 30℃, the first discharge capacity of 2SPVC is about 400.3 mAh·g-1 which is very close to its theoretical value (410.5 mAh·g-1) at a constant discharge current of 15 mA·g-1. It can retain at about 346.1 mAh·g-1 of discharge capacity after 30 charge-discharge cycles. So 2SPVC is a very promising cathode candidate for rechargeable lithium batteries.